High expression of insulin-like growth factor binding protein-2 messenger RNA in epithelial ovarian cancers produces elevated preoperative serum levels

The molecular etiology of epithelial ovarian cancer remains unclear. Using microarray expression analysis, we recently reported that expression of the insulin-like growth factor binding protein-2 (IGFBP-2) gene is elevated in advanced epithelial ovarian cancers. The aim of this study was to further delineate the role of IGFBP-2 in the pathoetiology of epithelial ovarian cancer and determine if elevated ovarian cancer IGFBP-2 gene expression is reflected in serum. Relative IGFBP-2 expression was measured using quantitative real-time polymerase chain reaction in 113 epithelial ovarian cancers and 6 normal ovarian surface epithelial samples. Preoperative serum IGFBP-2 levels were measured by radioimmunoassay in 84 women (42 ovarian cancers, 26 benign gynecological conditions, and 10 healthy female controls). Ovarian cancers demonstrated 38-fold higher mean IGFBP-2 expression than normal ovarian epithelium (P < 0.01). Serum IGFBP-2 levels were elevated in women with early- and advanced-stage ovarian cancer compared to controls and patients with benign gynecological conditions (P = 0.05 and P < 0.01, respectively). Epithelial ovarian cancers express high levels of IGFBP-2 relative to normal ovarian epithelium, and this is associated with elevated serum IGFBP-2 levels compared to both normal controls and patients with benign gynecological disease. Our findings provide further support that the insulin-like growth factor pathway plays a significant role in epithelial ovarian cancer pathogenesis. Further, IGFBP-2 may represent an additional serum biomarker with utility in detection and monitoring of epithelial ovarian cancer.

2-Methoxyestradiol, an endogenous estradiol metabolite, differentially inhibits granulosa and endothelial cell mitosis: a potential follicular antiangiogenic regulator

2-Methoxyestradiol (2-ME) is an estradiol metabolite with antiangiogenic and antitumor activity. It is formed by granulosa cell (GC) catechol-O-methyltransferase activity and is present in the normal follicle at high concentrations. In this unique microenvironment, it may regulate selected cell types via autocrine and/or paracrine action. To assess the possibility that 2-ME or estradiol might exert differential mitotic and/or apoptotic effects on endothelial cells and GCs, we compared their actions on primary cultures of hormone- and/or growth factor-stimulated porcine GCs (pGCs) as well as two types of endothelial cells, primary cultures of porcine endothelial cells (pECs), and a spontaneously transformed rabbit endothelial vascular cell (REVC) line. The 2-ME, but not estradiol, dose dependently suppressed tritiated thymidine ((3)H-T) incorporation into epidermal growth factor (EGF)-stimulated REVCs and EGF/insulin (INS)-stimulated pECs. In contrast, 2-ME did not attenuate incorporation in FSH/INS-stimulated pGCs. It reduced incorporation by approximately 50% in EGF/INS-stimulated pGCs, indicating that responsiveness to 2-ME in normal cells can be modulated by hormone and growth factor treatment. Estradiol was not antimitotic to pGCs. As indicated by 4',6-diamido-2-phenylindole hydrochloride nuclear staining, estradiol was nonapoptotic in either cell type, and 2-ME significantly increased apoptosis of REVCs, but not of pGCs. In a cell migration assay, REVC movement was attenuated by 2-ME, but not by estradiol. In summary, the results show that antimitotic as well as proapoptotic responses to 2-ME vary with cell type and, in the case of pGC antimitotic activity, with the regulatory microenvironment. Thus, they provide a rationale for autocrine and/or paracrine action of 2-ME at its site of production in vivo, and they strongly support the concept of 2-ME as a candidate ovarian angiogenesis inhibitor.

Prevention of the polycystic ovarian phenotype and characterization of ovulatory capacity in the estrogen receptor-alpha knockout mouse

Ovarian-derived estradiol plays a critical endocrine role in the regulation of gonadotropin synthesis and secretion from the hypothalamic-pituitary axis. In turn, several para/autocrine effects of estrogen within the ovary are known, including increased ovarian weight, stimulation of granulosa cell growth, augmentation of FSH action, and attenuation of apoptosis. The estrogen receptor-alpha (ERalpha) is present in all three components of the hypothalamic-pituitary-ovarian axis of the mouse. In contrast, estrogen receptor-beta (ERbeta) is easily detectable in ovarian granulosa cells but is low to absent in the pituitary of the adult mouse. This distinct expression pattern for the two ERs suggests the presence of separate roles for each in the regulation of ovarian function. Herein, we definitively show that a lack of ERalpha in the hypothalamic-pituitary axis of the ERalpha-knockout (alphaERKO) mouse results in chronic elevation of serum LH and is the primary cause of the ovarian phenotype of polycystic follicles and anovulation. Prolonged treatment with a GnRH antagonist reduced serum LH levels and prevented the alphaERKO cystic ovarian phenotype. To investigate a direct role for ERalpha within the ovary, immature alphaERKO females were stimulated to ovulate with exogenous gonadotropins. Ovulatory capacity in the immature alphaERKO female was reduced compared with age-matched wild-type (14.5+/-2.9 vs. 40.6+/-2.6 oocytes/animal, respectively); however, oocytes collected from the alphaERKO were able to undergo successful in vitro fertilization. A similar discrepancy in oocyte yield was observed after superovulation of peripubertal (42 days) wild-type and alphaERKO females. In addition, ovaries from immature superovulated alphaERKO females possessed several ovulatory but unruptured follicles. Investigations of the possible reasons for the reduced number of ovulations in the alphaERKO included ribonuclease protection assays to assess the mRNA levels of several markers of follicular maturation and ovulation, including ERbeta, LH-receptor, cyclin-D2, P450-side chain cleavage enzyme, prostaglandin synthase-2, and progesterone receptor. No marked differences in the expression pattern for these mRNAs during the superovulation regimen were observed in the immature alphaERKO ovary compared with that of the wild-type. Serum progesterone levels just before ovulation were slightly lower in the alphaERKO compared with wild-type. These studies indicate that treatment of alphaERKO females with a GnRH antagonist decreased the serum LH levels to within the wild-type range and concurrently prevented development of the characteristic ovarian phenotype of cystic and hemorrhagic follicles. Furthermore, a lack of functional ERalpha within the ovary had no effect on the regulation of several genes required for follicular maturation and ovulation. However, the reduced numbers of ovulations following the administration of exogenous gonadotropins in the alphaERKO suggests an intraovarian role for ERalpha in follicular development and ovulation.

Targeted disruption of the estrogen receptor-alpha gene in female mice: characterization of ovarian responses and phenotype in the adult

Targeted disruption of the mouse estrogen receptor-alpha gene (estrogen receptor-alpha knockout; ERKO) results in a highly novel ovarian phenotype in the adult. The ERKO mouse model was used to characterize ER alpha-dependent processes in the ovary. Visualization of the ovaries of 10-, 20-, and 50-day-old wild-type (WT) and ERKO mice showed that the ERKO phenotype developed between 20 and 50 days of age. Developmental progression through the primordial, primary, and antral follicle stages appeared normal, but functional maturation of preovulatory follicles was arrested resulting in atresia or in anovulatory follicles, which in many cases formed large, hemorrhagic cysts. Corpora lutea were absent, which also indicates that the normal biochemical and mechanical processes that accomplish ovulation were compromised. Northern and ribonuclease protection analyses indicated that ERKO ovary FSH receptor (FSHR) messenger RNA (mRNA) expression was approximately 4-fold greater than in WT controls. Ovarian LH receptor (LHR) mRNA expression was also higher in the ERKO animals. Cellular localization studies by in situ hybridization analysis of ERKO ovaries showed a high level of LHR mRNA expression in the granulosa and thecal layers of virtually all the antral follicles. Ribonuclease protection analyses showed that ovarian progesterone receptor and androgen receptor mRNA expression were similar in the two groups. These results indicated that ER alpha action was not a prerequisite for LHR mRNA expression by thecal or granulosa cells or for ovarian expression of progesterone receptor mRNA. Ovarian estrogen receptor beta (ER beta) was detected immunohistochemically, was sharply compartmentalized to the granulosa cells, and was expressed approximately equally in the ERKO animals and the WT controls. In contrast, ER alpha staining was present in the thecal cells but not the granulosa cells of the WT animals. The summary findings indicate that in the adult the major cause of the ERKO phenotype is high circulating LH interacting with functional LHR of the theca and granulosa cells. These features result in a failure of the normal maturational events leading to successful ovulation and luteinization and presumably involve both hypothalamic-pituitary and intraovarian mechanisms dependent upon ER alpha action. The presence of ER beta in the granulosa cells did not rescue the phenotype of the ovary.

Restricted expression of WT1 messenger ribonucleic acid in immature ovarian follicles: uniformity in mammalian and avian species and maintenance during reproductive senescence

WT1 is a zinc finger protein with transcriptional repressor activity on several growth factor and growth factor receptor genes. In the ovary, a potential role for WT1 in the suppression of the development of immature follicles has been demonstrated. Here, gel retardation assays further showed that recombinant WT1 protein interacted with consensus DNA sequences in the inhibin-alpha gene promoter. We investigated the pattern of WT1 expression in a wide variety of species and also over the reproductive life span in rats. In chicken ovaries, Northern blot analysis revealed the presence of WT1 transcript in small healthy white follicles (1-5 mm in diameter) and its absence in small yellow (6-12 mm in diameter) or larger follicles (F1-F5). In pig and monkey ovaries, WT1 expression was limited to granulosa cells of preantral follicles, as shown by in situ hybridization analysis. In rats, Northern blot analyses demonstrated the presence of WT1 transcript in the ovaries of young (3-mo-old) and middle-aged (9-mo-old) rats on the proestrous day, with a decrease in old (12-mo-old) rats in persistent estrus. In situ hybridization analysis further suggested that the decrease in WT1 expression in aging ovaries was associated with fewer immature follicles. Thus, WT1 expression is restricted to immature follicles in diverse avian and mammalian species and over the reproductive life span in rats. These data demonstrated that WT1 is a marker for immature follicles and suggested a potential role of this transcriptional repressor in the slow growth of early follicles.

Transforming growth factor beta modulates gonadotropin receptor expression in porcine and rat granulosa cells differently

Almost without exception, the studies to date describing the effects of transforming growth factor beta (TGF beta) upon various ovarian cell types have utilized the subtype TGF beta 1. Since TGF beta 1 and TGF beta 2 have been demonstrated to influence major developmental processes differentially during hematopoiesis and embryogenesis, we investigated in two species (rat and pig) whether they might also differentially modulate principal regulatory processes of ovarian cellular differentiation, specifically FSH and/or LH receptor (FSHR, LHR) expression. TGF beta 1 plus FSH significantly stimulated LHR binding levels by cultured granulosa cells (GC) from prepubertal diethylstilbestrol-treated rats. TGF beta 2 produced the same effect. In porcine GC from 1-3-mm antral follicles, TGF beta 1 and TGF beta 2 again acted similarly, but the direction of the response was opposite to that in the rat GC system. This difference could not be ascribed to the fact that the GC utilized represented different stages of follicular development in vivo because TGF beta 1 also potentiated FSH-dependent LHR induction in GC from antral follicles of cycling rats at all stages of the estrous cycle. The major effect of TGF beta 1 on FSHR expression in the rat system was to increase binding by attenuating the down-regulatory action of cholera toxin (CTX) or FSH. In the porcine system, TGF beta reduced FSHR binding at FSH or CTX concentrations that enhanced expression, and it did not attenuate the down-regulatory effect of FSH or CTX at higher doses. In summary, TGF beta up- or down-regulated LHR and FSHR binding coordinately within species.(ABSTRACT TRUNCATED AT 250 WORDS)

Porcine granulosa cells do not express transforming growth factor-beta 2 (TGF-beta 2) messenger ribonucleic acid: molecular basis for their inability to produce TGF-beta activity comparable to that of rat granulosa cells

In contrast to rat granulosa cells (GC), GC of the pig and cow produce very low levels of transforming growth factor-beta (TGF-beta)-like activity in vitro. Because cultured rat GC predominantly express TGF-beta 2 messenger RNA (mRNA) and secrete high levels of the protein, we hypothesized that TGF-beta 2 mRNA expression by porcine GC might be absent or diminished, thus providing a molecular explanation(s) for their relatively low levels of TGF-beta production. We tested this hypothesis by reverse transcription-polymerase chain reaction (RT-PCR) and enzyme-linked immunosorbent assay analysis. When analyzed by RT-PCR, porcine GC RNA from 1-3 mm follicles did not yield the expected 489 base pair (bp) TGF-beta 2 product but instead generated a smaller than anticipated 240 bp species; porcine testis RNA generated both the 240 and the anticipated 489 bp products. Sequencing these species indicated that the smaller form was not a novel TGF-beta 2 splice variant, and that the 489-bp product was porcine TGF-beta 2. This is the first reported nucleotide sequence for porcine TGF-beta 2; it is 90% and 91% identical to murine and human TGF-beta 2 sequences, respectively. Further RT-PCR analysis of porcine GC RNA resulted in the identification of bp products representing TGF-beta 1 and TGF-beta 3 mRNA. Enzyme-linked immunosorbent assay analysis of porcine GC conditioned medium confirmed the presence of TGF-beta 1 at very low levels. TGF-beta 2 was undetectable. Comparable analysis of GC from the diethylstilbestrol-treated prepubertal rat demonstrated the presence of TGF-beta 1 and TGF-beta 3 mRNA by RT-PCR and very low levels of the corresponding protein products in conditioned culture medium. Collectively, these results suggest that the inability of porcine GC to express TGF-beta 2 mRNA could explain the very low levels of TGF-beta activity secreted by these cells in vitro.

Apoptosis in atretic ovarian follicles is associated with selective decreases in messenger ribonucleic acid transcripts for gonadotropin receptors and cytochrome P450 aromatase

Although atresia of ovarian follicles is of critical importance during preovulatory follicle selection as well as during normal and premature menopause, the mechanisms underlying atresia remain poorly understood. To study molecular events associated with atresia, we evaluated changes in mRNA levels for cytochrome P450 aromatase, FSH receptor, LH receptor, and a structural protein, beta-actin, during atresia in small (3-mm diameter) and large (6-mm diameter) porcine follicles. In addition, internucleosomal fragmentation of DNA characteristic of apoptosis ("programmed cell death") was assessed in individual healthy and atretic follicles using a sensitive autoradiographic method. Follicles were classified as morphologically healthy or atretic based on the absence or presence of follicular haemorrhagia and the degree of follicular clarity. Morphological signs of atresia in individual follicles were correlated with the occurrence of internucleosomal DNA fragmentation in granulosa cells as well as in thecal cells during advanced stages of atresia. The presence of apoptosis in atretic follicles was also associated with significant decreases in follicular fluid estrogen concentrations compared to those in healthy follicles of the same size. The decline in estrogen synthesis in degenerating follicles was further correlated with decreased levels of a predominant 2.6-kilobase aromatase mRNA. Moreover, substantial declines in both FSH receptor and LH receptor mRNAs were found in atretic follicles, consistent with previous reports of their decreased responsiveness to gonadotropins. The observed decreases in mRNAs for aromatase and gonadotropin receptors could not be attributed to a generalized degradation of cellular RNA during atresia, as evidenced by the presence of intact 18S and 28S ribosomal RNA as well as constitutive expression of beta-actin mRNA in atretic follicles. These data indicate that apoptotic cell death is initiated in both granulosa and thecal cells of porcine follicles during atresia. Associated with internucleosomal DNA fragmentation, decreased transcription of specific ovarian genes or destabilization of their transcripts leads to selective decreases in aromatase and gonadotropin receptor mRNAs. The atresia of ovarian follicles provides an interesting model to further study the molecular events associated with DNA fragmentation and selective mRNA down-regulation during apoptosis.

Effects of diethylstilbestrol on rat granulosa cell and thecal/interstitial cell transforming growth factor-beta 2 mRNA expression in vivo: analysis by reverse transcription-polymerase chain reaction

Recent studies indicate that reproductive hormones may stimulate target cell growth via the actions of growth factors. In this study, reverse transcription-polymerase chain reaction analysis was used to assess the effects of in vivo diethylstilbestrol (DES) treatment on granulosa cell (GC) and thecal-interstitial cell (TIC) transforming growth factor (TGF)-beta 2 mRNA expression. In response to DES, GC expression of TGF-beta 2 mRNA was stimulated approximately 6.8-fold. By contrast, DES did not significantly alter TIC expression of TGF-beta 2 mRNA. Data were normalized relative to glyceraldehyde-3-phosphate dehydrogenase mRNA levels, which were unaffected by DES. These results extend our earlier findings, which demonstrated that GC and TIC expression of TGF-beta 2 mRNA is regulated by gonadotropins in vitro, to include steroidal regulation in vivo of intraovarian growth factor expression. Collectively, the present study and previous results support the following concepts: 1) intraovarian TGF-beta 2 mRNA expression is regulated by both gonadotropins and steroids, and 2) GC and TIC expression of TGF-beta 2 mRNA are differentially regulated.

Human granulosa-luteal and cumulus cells express transforming growth factors-beta type 1 and type 2 mRNA

Human granulosa-luteal cells and cumulus cells obtained from women undergoing in vitro fertilization and embryo transfer (IVF-ET) were examined for the presence of TGF-beta 1 and TGF-beta 2 mRNA by reverse transcription-polymerase chain reaction (RT-PCR) analysis. RT-PCR analysis revealed that both follicle cell types express mRNA for both TGF-beta subtypes. Verification of RT-PCR products was done by restriction enzyme digestion analysis. These results suggest a role(s) for TGF-beta 1 and TGF-beta 2 in the development of human granulosa-luteal cells and the oocyte-cumulus cell complex.

Rat thecal/interstitial cells express transforming growth factor-beta type 1 and 2, but only type 2 is regulated by gonadotropin in vitro

We previously demonstrated that granulosa cells from diethylstilbestrol-primed immature rats expressed transforming growth factor-beta 2 (TGF beta 2), but not TGF beta 1, mRNA and that its expression was regulated by FSH in vitro. The present studies were designed, therefore, to establish whether thecal/interstitial cells (TIC) from diethylstilbestrol-primed immature rats express more than one subtype of TGF beta mRNA and gene product and whether the levels of expression/production in vitro were regulated by LH/hCG. Reverse transcription-polymerase chain reaction (RT-PCR) analysis of total RNA indicated that TIC expressed both TGF beta 1 and TGF beta 2 mRNA. In response to hCG (200 ng/ml), TIC expressed TGF beta 2 mRNA levels that were 51% of control levels; TGF beta 1 mRNA levels were not altered. In response to cholera toxin (10(-9) M), TIC expression of TGF beta 2 and TGF beta 1 mRNA levels was 10% and 55% of control values, respectively. Western blot analysis established that both TGF beta 1 and TGF beta 2 were secreted in vitro. hCG and cholera toxin reduced secretion of TGF beta bioactivity by 55% and 90%, respectively. In summary, these results indicate: 1) TIC express both TGF beta 1 and TGF beta 2 mRNA; 2) TIC expression of TGF beta 2, but not TGF beta 1, mRNA is regulated by hCG in vitro; 3) TIC secrete both TGF beta 1 and TGF beta 2, and 4) TIC secretion in vitro of TGF beta activity is gonadotropin regulated.

Acute and subacute effects of naturally occurring estrogens on luteinizing hormone secretion in the ovariectomized rat: Part 2

Acute intravenous administration of the phytoestrogen genistein (G) blocks the gonadotropin-releasing hormone-(GnRH)-induced rise of luteinizing hormone (LH) in ovariectomized rats. The present experiments were performed to determine whether subacute administration of G or the mycoestrogens zearalenone and zearalenol would affect GnRH-induced or progesterone-induced LH secretion in ovariectomized rats. Charles River CD rats were ovariectomized and used 2 to 5 weeks later. Blood samples were obtained either via decapitation or via intraatrial cannulae three days after compounds were injected subcutaneously in sesame oil or corn oil vehicle. LH was measured by RIA. Pretreatment with estradiol benzoate suppressed LH levels at 1200 h, while G had no effect. Challenge with progesterone (8 mg/kg BW, sc) evoked LH release at 1600 h in rats pretreated with estradiol benzoate, but LH levels did not change in rats pretreated with G, zearalenone, or zearalenol. While GnRH-induced LH secretion was preserved in rats pretreated with estradiol, no LH response was detected in rats pretreated with the higher dose of G (8 mg/kg BW) or either dose of zearalenol (0.8 mg/kg BW or 8 mg/kg BW). We conclude that in the ovariectomized rat 1) subacute administration of G, zearalenone, or zearalenol do not inhibit tonic LH secretion, 2) G, zearalenone, and zearalenol do not provide "estrogenic priming" for progesterone-induced LH secretion; however, 3) G and zearalenol do block GnRH-induced LH secretion. The seemingly selective neuroendocrine effects of these naturally-occurring dietary estrogens emphasize that actions of each putative estrogen must be characterized for each "estrogenic" endpoint.

Rat granulosa cells express transforming growth factor-beta type 2 messenger ribonucleic acid which is regulatable by follicle-stimulating hormone in vitro

Freshly harvested granulosa cells (GC) from diethylstilbestrol (DES)-treated rats were examined for the presence of transforming growth factor-beta 1 (TGF-beta 1) and TGF-beta 2 mRNA by Northern analysis. TGF-beta 1 mRNA was not detectable, but hybridization of total RNA with a radiolabeled TGF-beta 2 cDNA probe revealed two mRNA species (5.1 and 3.6 kb) indicative of TGF-beta 2 mRNA. In response to FSH (50 ng/ml), relative TGF-beta 2 mRNA concentrations in cultured GC were 54% of control levels. Furthermore, the conditioned culture medium from FSH-treated GC contained significantly lower (p less than 0.01) TGF-beta-like activity relative to controls. These results demonstrate that rat GC express TGF-beta 2 mRNA which is regulatable by FSH in vitro.

The production of transforming growth factor-beta activity by rat granulosa cell cultures

We have examined whether granulosa cells (GC) secrete transforming growth factor-beta (TGF beta)-like activity using cell cultures prepared from diethylstilbestrol-primed female rats. Our results indicate that a significant level of active as well as latent TGF beta activity is found in defined GC culture medium as assessed by 1) potentiation of FSH-induced differentiation of rat GC, 2) neutralization of its activity by anti-TGF beta immunoglobulin, 3) inhibition of DNA synthesis in mink lung epithelial cells (CCl 64), and 4) activation of latent TGF beta activity by either acid or heat treatment. TGF beta production was more pronounced when the cells were seeded on fibronectin-coated plates. There was no difference in the level of TGF beta secretion by GC preparations derived from either diethylstilbestrol-primed immature or normal immature rats or adult rats. Furthermore, rat GC-conditioned medium contained much more TGF beta activity than medium from normal rat kidney cells (NRK 49-F), human prostatic adenocarcinoma cells (PC-3), or porcine GC. Rat thecal/interstitial cell culture medium contained activity comparable to that of GC medium. We conclude that rat GC preparations secrete a high level of TGF beta activity in vitro. Taken together with previous results, this indicates the possibility that TGF beta may be an autocrine regulator as well as a paracrine one within the ovarian follicle. Moreover, because of the high level of TGF beta activity produced, the rat GC culture system appears to be a useful experimental model for further exploring relationships between TGF beta production and its action.

Human platelet-derived growth factor preparations contain a separate activity which potentiates follicle-stimulating hormone-mediated induction of luteinizing hormone receptor in cultured rat granulosa cells: evidence for transforming growth factor-beta

The ability of platelet-derived growth factor (PDGF) preparations to potentiate FSH-mediated LH receptor induction in rat granulosa cell cultures was shown to be due to a component distinct from PDGF. Purification of heat-treated platelet lysate by carboxymethyl-Sephadex C-50 and Cibacron blue-Sepharose chromatography, followed by Bio-Gel P-60 chromatography, resulted in the separation of two activities: 1) a growth-promoting activity, P60-PDGF, defined on the basis of increased DNA synthesis in BALB/c-3T3 cells, and 2) a differentiation-promoting activity which enhanced FSH-dependent LH receptor induction in granulosa cells. On the basis of electrophoretic mobility on sodium dodecyl sulfate-polyacrylamide gels, inhibition of tritiated thymidine uptake by epithelial cells, and attenuation of LH/hCG receptor expression in the presence of antitransforming growth factor-beta (anti-TGF beta) immunoglobulin G, the differentiation-promoting component of the preparations appears to be TGF beta. The Bio-Gel fractions that contained TGF beta did not stimulate LH receptor induction of cAMP production in the absence of FSH. PDGF prepared free of TGF beta did not potentiate receptor induction. We conclude, therefore, that the differentiative effects of PDGF previously described in this system are due to TGF beta.

Synergistic effect of insulin and follicle-stimulating hormone on biochemical and morphological differentiation of porcine granulosa cells in vitro

Insulin and follicle-stimulating hormone (FSH) have been shown to facilitate granulosa cell differentiation in vitro. To gain insight into this process, we evaluated the effects of these hormones, alone and in combination, upon the biochemical parameters of luteinizing hormone/human chorionic gonadotropin (LH/hCG) receptor induction and progesterone secretion concomitantly with morphometric analysis of granulosa cell ultrastructure and LH/hCG receptor distribution by quantitative autoradiography under light microscopy. Granulosa cells isolated from small antral follicles (controls) cultured in the absence of exogenous hormones exhibited few microvilli and gap junctions; the mitochondria, endoplasmic reticulum, and Golgi complex were all poorly developed. Progesterone secretion was negligible and the cells bound little [125I]iodo-hCG. Insulin treatment increased gap junction formation, and the extent of smooth and rough endoplasmic reticulum and Golgi complex development (all p less than 0.05) but did not affect mitochondrial ultrastructure or volume. Insulin treatment modestly but significantly increased [125I]iodo-hCG binding and progesterone secretion relative to controls (p less than 0.001). FSH treatment had a similar effect to insulin on cell ultrastructure and additionally enhanced development of the mitochondria and smooth endoplasmic reticulum as well as formation of the microvilli (p less than 0.05). FSH significantly increased [125I]iodo-hCG binding and progesterone secretion relative to insulin-treated samples (p less than 0.001). Combined treatment with insulin and FSH markedly increased gap junction and microvilli formation and enhanced the development of the smooth endoplasmic reticulum and the Golgi complex relative to treatment with either hormone alone (p less than 0.05). Additionally, the combined treatment produced larger mitochondria with tubular christae. Consistent with the morphological development, the combined treatment of insulin and FSH significantly increased progesterone secretion and [125I]iodo-hCG binding (p less than 0.001). Autoradiographic analysis showed that aggregated cells in general exhibited higher LH/hCG receptor density than nonaggregated cells, and a significantly higher overall receptor density compared to nonaggregated cells or to cells treated either with insulin or FSH alone. Our results indicate that insulin and FSH facilitate morphological differentiation of the granulosa cell in a synergistic manner, stimulating gap junctions and microvilli formation and enhancing development of the mitochondria, endoplasmic reticulum, and Golgi complex.(ABSTRACT TRUNCATED AT 400 WORDS)

Differential effects of epidermal growth factor, somatomedin-C/insulin-like growth factor I, and transforming growth factor-beta on porcine granulosa cell deoxyribonucleic acid synthesis and cell proliferation

Recent studies have suggested that the mammalian ovary synthesizes epidermal growth factor (EGF), somatomedin-C/insulin-like growth factor I (Sm-C), and transforming growth factor-beta (TGFb) and that these growth factors may in part form a basis for intraovarian regulation of granulosa cell proliferation and differentiation. The studies described herein were initiated to determine to what extent EGF, Sm-C, and TGFb function to regulate DNA synthesis and granulosa cell proliferation during primary monolayer culture. EGF, but neither Sm-C nor TGFb, alone consistently stimulated, in a dose-dependent manner, [3H]thymidine incorporation by porcine granulosa cells under defined conditions (P less than 0.01). Sm-C (10 ng/ml) and TGFb (1 ng/ml) both enhanced EGF-stimulated [3H]thymidine incorporation (56% and 300%, respectively; P less than 0.05). The levels of incorporation obtained with EGF plus TGFb were equal to or greater than those obtained using fetal bovine serum alone. When EGF, Sm-C, and TGFb were combined, [3H]thymidine incorporation was equivalent to that obtained with EGF plus 10% fetal bovine serum, heretofore the most potent stimulatory combination for [3H]thymidine incorporation. Thus, under defined conditions, EGF, Sm-C, and TGFb act synergistically to promote DNA synthesis in primary cultures of porcine granulosa cells. Although DNA synthesis is a requisite step for but is not an accurate measurement of cell proliferation per se, we investigated whether the observed effects of EGF, Sm-C, and TGFb on DNA synthesis were realized in terms of actual cell proliferation. This was accomplished using platelet-poor plasma-derived serum (PPPDS; 0.1-2.5%), which contains reduced levels of endogenous growth factors but not components needed for cell attachment. EGF (P less than 0.05), but neither Sm-C nor TGFb, alone consistently stimulated, in a dose-dependent manner, granulosa cell proliferation, an effect directly related to the PPPDS concentration. Sm-C consistently and significantly (P less than 0.05) enhanced EGF-stimulated cell proliferation in a dose-dependent manner. The facilitative effect of Sm-C was inversely related to the PPPDS concentration, ranging from a 76 +/- 15% increase at 0.1% PPPDS to a 14% increase at 1.0% PPPDS. TGFb exhibited a bifunctional effect on granulosa cell proliferation. At low levels of PPPDS (0.1% and 0.25%) and in the absence of Sm-C, TGFb enhanced EGF-stimulated cell division, an effect which, although small and variable (24 +/- 16%), was consistent.(ABSTRACT TRUNCATED AT 400 WORDS)

[125I]iodo-epidermal growth factor binding and mitotic responsiveness of porcine granulosa cells are modulated by differentiation and follicle-stimulating hormone

Epidermal growth factor (EGF) stimulates granulosa cell (GC) proliferation of certain species and modulates FSH-induced GC differentiation. The present study was undertaken to characterize the binding properties of the EGF receptor in porcine GCs to determine if the EGF responsiveness of mitotically active porcine GCs was related to their differentiated state and was regulated by reproductive hormones in vitro. Characterization of the EGF receptor-binding properties of porcine GCs revealed that saturation binding was achieved with 10 ng/ml [125I]iodo-EGF after 1 h at 37 C. In all states of differentiation, porcine GCs expressed few (less than 20,000/cell), specific, high affinity EGF receptors with apparent Kd values of 5.5 +/- 0.7 X 10(-10) M (mean +/- SEM; n = 6). Freshly harvested GCs obtained from small follicles were considered slightly differentiated (SDs) and bound, on the average, 2.6-fold more [125I]iodo-EGF than highly differentiated cells (HDs) obtained from large follicles which had further differentiated in vivo. The difference in binding was due to a decrease in receptor number and not to a change in receptor affinity. This relationship observed in freshly harvested cells was maintained in culture for a limited period. At 48 h of culture, the [125I]iodo-EGF-binding capacity of SDs was higher than that of HDs and was inversely related to the state of differentiation, as measured by [125I]iodo-LH/hCG-binding capacity. After 96 h, however, the EGF-binding capacity of HDs increased 3.7-fold from the level of binding at 48 h, while the LH/hCG-binding capacity decreased 10-fold. Conversely, the EGF-binding capacity of SDs decreased 28%, while the LH/hCG-binding capacity remained low. These experiments indicated that the state of GC differentiation was inversely correlated with EGF receptor number and that this relationship was not maintained in culture beyond 48 h. FSH treatment within the first 48 h of culture decreased the EGF-binding capacity of SDs 35% relative to the control value, but estradiol and dihydrotestosterone had no effect. FSH also regulated the mitotic responsiveness to EGF. EGF treatment of cultured SDs stimulated an 84% increase in cell number and a 178% increase in [3H]thymidine incorporation. These effects were suppressed by a high concentration of FSH. Thus, the ability of porcine GCs to bind EGF was changed with differentiation in vivo, while both EGF-binding capacity and mitotic responsiveness were regulated by exposure to FSH in vitro.

Epidermal growth factor enhances [125I]iodo-follicle-stimulating hormone binding by cultured porcine granulosa cells

Epidermal growth factor (EGF) has been shown to have diverse effects on granulosa cells (GC). Although a potent mitogen for GC from several species, EGF attenuates many FSH-mediated processes associated with GC differentiation, suggesting that EGF promotes cell proliferation at the expense of cell differentiation. The extent to which EGF effects involve modulation of the FSH receptor level in proliferating GC has not been established. Accordingly, we investigated the effect of EGF on [125I]iodo-FSH binding by porcine GC isolated from small follicles maintained in monolayer cultures. Relative to cells cultured in medium with insulin alone, EGF treatment increased total monolayer [125I]iodo-FSH binding (per culture) 120% (P less than 0.005). This was due to a 40-50% (P less than 0.01) increase in binding per U protein and/or per U cell and a 40-60% (P less than 0.005) increase in both monolayer cell and protein contents. EGF stimulated GC hyperplasia, but not hypertrophy. Optimum EGF doses for increased total monolayer [125I]iodo-FSH binding and binding normalized per U protein or cell were 0.5 and 0.1 ng/ml, respectively. Fibroblast growth factor was 20- to 100-fold less potent than EGF, and thrombin was without effect. Whereas [125I]iodo-FSH binding per U protein or cell was not affected by the serum concentration of the culture medium, the EGF effects on total monolayer binding and cell proliferation were directly related to the serum concentration (P less than 0.005). Thus, EGF-mediated increases in total monolayer [125I]iodo-FSH binding were paralleled by increases in cell number. The equilibrium dissociation constants (Kd) for [125I]iodo-FSH binding to cells cultured with and without EGF were 5.3 and 2.5 X 10(-10) M, respectively. Thus, EGF treatment significantly increased FSH receptor number, but significantly decreased receptor-binding affinity (P less than 0.05). Chronic FSH treatment during monolayer culture decreased total monolayer [125I]iodo-FSH binding and binding per U protein or per cell and attenuated EGF-stimulated cell proliferation, but markedly stimulated cell hypertrophy. Thus, concomitant treatment with EGF and FSH stimulated cell hypertrophy rather than hyperplasia. EGF and FSH each would appear capable of modulating the action of the other with respect to GC function. Our results indicate that EGF-mediated GC proliferation is associated with the expression of FSH-binding sites. This appears to be due to both an increase in FSH receptors among the cell population and an increase in the monolayer cell population.(ABSTRACT TRUNCATED AT 400 WORDS)

Estrogen and progesterone production by granulosa cell monolayers derived from in vitro fertilization procedures: lack of evidence for modulation by androgen

The role(s) of androgens in the steroidogenic regulation of human granulosa cell production of estrogen and progesterone during monolayer culture was studied. These cells were exposed in vivo to human menopausal gonadotropin and hCG gonadotropin with or without clomiphene citrate. Steroid production rates were compared between cells cultured in control medium and those cultured in medium containing a nonaromatizable androgen [dihydrotestosterone (DHT)] or an aromatizable androgen [androstenedione (A'D)]. Some cultures received A'D from 3-12 days; other cultures received DHT alone for 3, 6, or 9 days before the addition of A'D for 3 days. The effect on steroid production during the culture interval before the addition of A'D also was evaluated. Exposure to A'D increased estrogen production over 50-fold compared with that in control cells or those treated with DHT (P less than 0.001). DHT also failed to alter estrogen production when A'D was added to cultures. Furthermore, the delay in introducing A'D to the cultures for up to 9 days did not decrease subsequent estrogen production compared with that in cultures continually exposed to A'D or DHT plus A'D. Progesterone production was substantial for at least 12 days of culture and was unaffected by the presence of androgen. These results do not confirm previous studies using murine or porcine granulosa cells, which suggested that androgen receptor-dependent mechanisms were involved in increasing estrogen and/or progesterone production in vitro. Rather, they indicate that androgen may not be required to maintain aromatase capability per se in human granulosa-luteal cells previously exposed to ovulation-inducing quantities of gonadotropin.

The effect of transforming growth factor-beta on follicle-stimulating hormone-induced differentiation of cultured rat granulosa cells

Growth factors have been shown to modulate differentiation of cultured ovarian granulosa cells. Transforming growth factors (TGFs) constitute a family of polypeptide growth factors capable of reversibly inducing anchorage-independent growth in normal cells. Epidermal growth factor (EGF), which has significant structural homology with TGF alpha, has been shown to modulate differentiation of granulosa cells in vitro. Similarly, TGF beta (TGFB) has been found to have significant structural homology with ovarian follicular fluid inhibin. To examine whether TGFB might affect granulosa cell growth or differentiation, rat granulosa cells were cultured in serum-free medium containing insulin for up to 3 days with varying concentrations of TGFB in the presence or absence of FSH. TGFB caused a dose-dependent increase in FSH-stimulated LH/hCG receptor binding, but had no effect on binding in the absence of FSH; TGFB (10.0 ng/ml) further increased FSH-stimulated LH/hCG receptor binding by 48 +/- 8% (P less than 0.02). Similarly, FSH-stimulated progesterone production was increased by TGFB in a dose-dependent manner; TGFB (1.0-10.0 ng/ml) increased FSH-stimulated progesterone production 2- to 3-fold (P less than 0.02). In contrast, EGF (10.0 ng/ml) decreased FSH-stimulated LH/hCG receptor binding by 93 +/- 1% (P less than 0.02). Neither FSH-stimulated intracellular nor extracellular cAMP accumulations were affected by TGFB treatment. However, EGF (10.0 ng/ml) diminished extracellular and intracellular FSH-stimulated cAMP accumulation at 48 and 72 h of culture. Culture protein and DNA content were not significantly affected by TGFB. These results suggest that TGFB may enhance FSH-stimulated LH receptor induction and steroidogenesis by mechanisms that do not further increase net cellular cAMP accumulation; TGFB and EGF can have opposite effects on gonadotropin-dependent differentiation; and products of the TGFB/inhibin gene family may have a capacity for autocrine or paracrine modulation of granulosa cell differentiation.

A serum-free defined culture system which maintains follicle-stimulating hormone responsiveness and differentiation of porcine granulosa cells

A serum-free defined culture system has been developed that maintains follicle-stimulating hormone (FSH)-dependent differentiation of porcine granulosa cells from small follicles for up to six days in culture. Confluent monolayers of epithelioid cells were established after culture on fibronectin-coated culture dishes (FBN, 2 micrograms/cm2) in nutrient medium supplemented with human low-density lipoprotein (LDL, 10 micrograms/ml), insulin (I, 1 microgram/ml), and thrombin (TH, 1 NIH U/ml). Each of these factors was necessary to maintain the epithelioid morphology of the monolayers that attained 70% of the protein content and 71% of the cell number of replicate cultures maintained in nutrient medium supplemented with 10% fetal calf serum and insulin. Addition of FSH to the FBN/LDL/I/TH-supplemented cultures resulted in dose-dependent increases in progesterone secretion and [125I]-iodo-human chorionic gonadotropin (hCG) binding comparable to those obtained in the cultures containing serum. These results indicate that the attachment, epithelioid morphology, and differentiated function of porcine granulosa cells (GCs) can be maintained in defined culture conditions. This culture system will facilitate study of the effects of growth promoters and differentiative agents on GC function in the absence of poorly defined serum supplements.

Compartmental ovarian steroidogenesis in polycystic ovary syndrome

Compartmental ovarian steroidogenesis in vitro was investigated in polycystic ovary syndrome. Basal estrogen secretion by granulosa cells ranged from 60 to 284 pg/micrograms cell protein for 24 hours and progesterone secretion from 24 to 1646 pg/micrograms cell protein for 24 hours. In three of four specimens, the addition of either 10(-5)M testosterone or androstenedione significantly increased estrogen production, demonstrating the presence of aromatase activity. Treatment with human follicle-stimulating hormone (100 ng/mL) or human chorionic gonadotropin (100 ng/mL) significantly increased the progesterone production in three of four specimens. The thecal compartment of every patient secreted significantly more testosterone and androstenedione than the capsule and stroma and more estrogen in tissue from two of the four women. The androgen/estrogen ratio was significantly greater for the theca (16.9) than the capsule (1.1) or stroma (1.7). These data demonstrate that in polycystic ovary syndrome a portion of the follicles possess the qualitative characteristics of developing follicles, granulosa cell aromatase activity and gonadotropin responsiveness, and that the theca is likely the principal site of ovarian androgen synthesis. These findings suggest that the small follicles characteristic of polycystic ovary syndrome consist of a mixed population of developing and atretic follicles and that the peripheral androgen excess is attributable to the large mass of the thecal compartment from both follicle populations.

Steroidogenesis in porcine atretic follicles: loss of aromatase activity in isolated granulosa and theca

To evaluate the mechanisms involved in the reduction of estrogen concentrations in porcine follicular fluid during atresia, nonatretic and atretic follicles ranging from 4 to 7 mm in diameter were selected. Follicular fluid estrogen concentrations were 7-16-fold less in the atretic follicles. Isolated granulosa cells from atretic follicles demonstrated a significant reduction in aromatase activity and in follicle-stimulating hormone (FSH)-induced progesterone production in vitro compared to granulosa cells from nonatretic follicles. Isolated theca from atretic follicles also demonstrated a reduction in estrogen production. However, androgen concentrations were equivalent in the follicular fluid of atretic and nonatretic follicles, and theca from atretic follicles maintained testosterone and androstenedione production in vitro. The loss of thecal aromatase activity with atresia is not secondary to a reduction in FSH responsiveness, since FSH did not increase thecal progesterone production in vitro. Cell degeneration also does not account for the reduction in thecal estrogen production, since both androgen output in vitro and follicular fluid androgen concentrations were maintained. These data thus demonstrate that a mechanism other than reduced FSH responsiveness must account for the selective loss of thecal aromatase activity in this stage of atresia.

A model system for the biochemical study of luteinizing hormone/chorionic gonadotropin receptor synthesis

A model system for the biochemical study of LH/CG receptor synthesis has been developed. Culture conditions for porcine granulosa cells were adapted that maximized the selective induction of LH/CG receptors by cAMP-inducing stimuli with an elimination of background LH/CG receptor appearance. It was found that the addition of FSH (1.5 micrograms/ml) or cholera toxin (10 ng/ml) 1 day after plating resulted in optimal induction of the LH/CG receptor (20-60 pg [125I]CG bound/micrograms DNA 72 h after addition) with virtually no LH/CG receptor appearance in the absence of added stimuli. Later additions of FSH or cholera toxin required insulin (1.0 microgram/ml) which alone caused background LH/CG receptor appearance in the absence of any additional stimuli. Furthermore, insulin increased the general rate of cellular protein synthesis, whereas FSH or cholera toxin each decreased it. Thus, the use of FSH or cholera toxin, without insulin, may enable one to detect the synthesis of the LH/CG receptor by metabolic labeling techniques where background protein synthesis has been lowered.

Effects of partially and more highly purified platelet-derived growth factor preparations on luteinizing hormone receptor induction in granulosa cell cultures

The effects of partially and more highly purified platelet-derived growth factor (PDGF) preparations on luteinizing hormone (LH) receptor induction by follicle-stimulating hormone (FSH) and cholera toxin (CTX) were studied in cultured granulosa cells from immature, diethylstilbestrol-primed rats. Partially purified PDGF, prepared by carboxymethyl Sephadex C-50 chromatography (CMS-PDGF), and more highly purified PDGF, further purified by Cibacron Blue Sepharose chromatography (BS-PDGF), enhance FSH-dependent LH receptor induction in serum-free and in serum-containing medium. BS-PDGF is more potent than CMS-PDGF, and is relatively more efficacious in serum-free and less efficacious in serum-containing medium than CMS-PDGF. CMS-PDGF and BS-PDGF enhance LH receptor induction by CTX in serum-containing medium, but levels achieved are significantly less than those attained with FSH and CMS- or BS-PDGF. BS-PDGF does not enhance induction by CTX in serum-free medium. The results suggest that the action of PDGF to enhance LH receptor induction is complex and may represent actions of several components of PDGF preparations. These findings may also provide indirect evidence for a component of FSH action which is independent of cAMP.

The effect of plating density on granulosa cell growth and differentiation in vitro

The extent of FSH-mediated LH/hCG receptor induction and of basal and FSH-stimulated progesterone production by porcine granulosa cells in vitro, in serum-containing medium, is directly related to the plating density. Relative to pre-culture levels, low- and high-density cultures of cells routinely exhibited 1-2- and 10-11-fold increases in [125I]iodo-hCG binding, respectively. Monolayer growth, i.e. cell division, as measured by increases in cell protein or DNA content, was inversely related to plating density. This density-directed inverse relationship between growth and differentiation did not appear to be coupled under the conditions utilized. Whereas monolayer growth was dependent upon the cell surface density, i.e. the number of cells per unit surface area, differentiation was dependent upon cell concentration, i.e. cells per unit volume of medium. Cells plated at low density in medium containing 10% serum exhibited 50% less [125I]iodo-hCG binding than cells in 5% serum (P less than 0.025). Conversely, cells plated at high density exhibited a 14% increase (P less than 0.025) in binding at the higher serum level. Thus, it appears that the extent of differentiation depends upon the capacity of cells to neutralize serum inhibition which in turn is dependent upon the cell concentration. Serum neutralization by granulosa cells is an FSH-dependent process. Conditioned medium derived from insulin-treated, high-density cultures did not facilitate optimum LH/hCG receptor induction in low-density cultures. Conditioned medium from cultures treated with insulin plus FSH, however, facilitated LH/hCG receptor induction in low-density cultures to the same extent as obtained in high-density cultures. The enhancement by FSH-conditioned medium cannot be attributed to residual FSH or to dilution of serum components during the preparation of the conditioned medium. The phenomena of serum-attenuated granulosa cell differentiation in vitro, and of a density-dependent reversal of this process, may have regulatory implications in vivo since follicular fluid contains many serum components and since the granulosa cell complement is an important determinant of follicle maturation.

Developmental coordination of luteinizing hormone/human chorionic gonadotropin (hCG) receptors and acute hCG responsiveness in cultured and freshly harvested porcine granulosa cells

A fundamental characteristic of ovarian antral follicle development is the progressive differentiation of the granulosa cells, a process marked by an increase in their complement of LH receptors. In this study we investigated the coordinated expression of [125I]iodo-hCG binding sites and hCG-sensitive cAMP production in intact cells from normally differentiating antral follicles of increasing size and in cells maintained in monolayer culture under conditions known to facilitate differentiation. In addition to hCG responsiveness, basal, FSH-stimulated, and cholera toxin-stimulated cAMP production were compared. Granulosa cell [125I]iodo-hCG binding capacity was directly related to follicle size; thus, binding provided a convenient marker of cell maturation, which, in turn, reflected the state of follicle development. Basal and hCG-stimulated cAMP production increased as a function of cellular LH/hCG receptor binding. Whereas basal activity increased linearly and proportionately with LH/hCG receptor binding, hCG-stimulated cAMP production was not linearly proportional. FSH responsiveness in terms of cAMP production declined as a function of LH/hCG receptor binding, exhibiting first order decay. While the patterns of FSH- and hCG-stimulated cAMP production were inversely related throughout much of follicle development, cholera toxin (CTX) responsiveness of cells remained constant until the very late preovulatory stages. Granulosa cells from large follicles (mean diameter, greater than 8 mm), having been exposed to the endogenous LH surge, exhibited high [125I]iodo-hCG binding but severely impaired hCG- and CTX-stimulated cAMP production, suggesting desensitization of adenylyl cyclase. In cultured granulosa cells, increased [125I]iodo-hCG binding induced by insulin and FSH was paralleled by an increased ability to generate cAMP in response to hCG. This coordinated expression of receptor and responsiveness was similar to that observed with progressively higher states of differentiation in freshly harvested cells. CTX-stimulated cAMP production in cells maintained in vitro was elevated and independent of LH receptor levels and, thus, was similar to that exhibited by freshly harvested cells. Granulosa cell cAMP production in response to acute FSH stimulation after chronic FSH treatment during culture was consistently lower than that of freshly harvested cells, a phenomenon that appeared to be related to the chronic dose of FSH used in vitro.(ABSTRACT TRUNCATED AT 400 WORDS)

Interactions between hormones and growth factors in the regulation of granulosa cell differentiation in vitro

Evidence from studies in vitro supports the concept that growth factors modulate endocrine-dependent differentiative processes in follicle development. Based upon results from granulosa cell culture systems, it is suggested that the study of growth factors and their regulatory mechanisms (endocrine, paracrine, autocrine control) could perhaps be generalized to other areas concerned with the regulation of steroid secretion such as placental physiology, the regulation of fetal gonads and puberty, secondary steroid metabolism and steroid-secreting tumors.

The dehydroepiandrosterone loading test. IV. Evaluation of clinical utility

This report complements the previously described preliminary clinical evaluation of the dehydroepiandrosterone (DHEA) loading test (DLT) by presenting the results of 65 DLTs in 59 patients. In patients whose fetuses were suspected of being intrauterine growth retarded, a DHEA to estrogen conversion rate constant less than or equal to 3.0 x 10(-3) min(-1) was associated with a birth weight below the tenth percentile in 60% of the pregnancies, whereas a conversion rate constant above this threshold was not associated with the same degree of growth retardation. The DLT continues to qualify as an accurate predictor of pregnancy outcome as judged by birth weight. Although it seems to be too cumbersome to serve as a screening technique, the DLT will permit evaluation of the efficacy of various pregnancy interventions directed toward improvement of the intrauterine environment, such as bed rest, tocolysis, or antihypertensive medication.

Platelet-derived growth factor enhances granulosa cell luteinizing hormone receptor induction by follicle-stimulating hormone and serum

Platelet-derived growth factor potentiated FSH-dependent LH receptor induction in serum-free and serum-containing cultures of rat granulosa cells. Levels of LH receptor binding comparable to pre-ovulatory levels could be achieved in vitro using a combination of FSH, platelet-derived growth factor, and serum. Receptor sites induced under these conditions were capable of mediating an hCG-stimulated increase in progestin secretion. Our results in vitro suggest a possible role for platelet-derived growth factor or related compounds in granulosa cell differentiation in vivo.

Growth factors modulate gonadotropin receptor induction in granulosa cell cultures

Epidermal growth factor and fibroblast growth factor inhibited follicle-stimulating hormone-dependent induction of luteinizing hormone receptor in cultured ovarian granulosa cells of the rat. In contrast, platelet-derived growth factor potentiated the induction of luteinizing hormone receptor by follicle-stimulating hormone. These results indicate that growth factors, well known for their effects on mitosis and DNA synthesis in cultured mammalian cells, are also able to modulate hormone-dependent differentiation in an endocrine target cell.

Follicle-stimulating hormone-mediated induction of functional luteinizing hormone/human chorionic gonadotropin receptors during monolayer culture of porcine granulosa cells

The LH/hCG receptor content of porcine ovarian granulosa cells from 1- to 3-mm follicles can be increases to 4--5 times the preculture level during monolayer culture in serum-containing media supplemented with insulin and FSH. The binding of [125I]iodo-hCG declines during the first 2 days of culture, but then uniformly increases through 6 days, achieving a 14- to 15-fold increase relative to the 2-day level under optimal conditions. Analysis of receptor binding by autoradiography indicates that after 2 days, the number of cells specifically binding [125I]iodo-hCG increases significantly during culture, as does the intensity of binding on receptor-bearing cells. Granulosa cells in monolayer culture exhibit heterogeneous receptor induction, indicating that normalized [125I]iodo-hCG binding data cannot be used to estimate receptor concentration per cell. Receptor affinities in the initial and induced populations are identical. LH/hCG receptors induced in granulosa cells during culture are functional, as demonstrated by specific hCG-stimulated progesterone secretion. 17 beta-Estradiol produces a differential effect in vitro, generally increasing [125I]iodo-hCG binding with respect to FSH-induced levels but consistently depressing the subsequent hCG-stimulated steroidogenic response of cells bearing the induced receptor. The porcine granulosa cell monolayer system thus appears to be a useful model with which to study, in vitro, mechanisms of steroid and gonadotropin regulation of granulosa cell differentiation and overall follicular development.

The dehydroepiandrosterone loading test. III. A possible placental function test

The dehydroepiandrosterone loading test (DLT) has been used in a small population of normal and high-risk obstetric patients, to date, in an attempt to develop a dynamic test of placental function. In spite of its limited applications, it has shown reliability in discriminating, with statistical significance, between high-risk pregnancies that result in normally grown, undistressed infants, and high-risk pregnancies that result in infants showing signs of placental insufficiency. The present report expands the study population by presenting our data on 40 loading tests performed in 37 high-risk and normal obstetric patients. Results of 19 of these DLT's have been previously reported and are included herein for statistical analysis. The DLT utilizes an excess substrate load of dehydroepiandrosterone to assess the maximum capability of the placenta to convert it to estrogen. Although our previous report did not show false positive or negative results in the conversion rates, the present results (40 DLT's) found two (2 out of 17) false positives (12%) and two (2 out of 19) false negatives (11%). The highly significant correlation between DLT result and pregnancy outcome seen previously was preserved. In addition, the data of another five DLT's in four patients are presented. This group includes a pregnancy with a fetus with multiple congenital malformations, two patients with intrauterine fetal death, and a nonpregnant woman. The results are not included in the statistical analysis, but discussion of these results has interesting pathophysiologic implications.

Steroidal modulation of steroid secretion in vitro: an experimental approach to intra-follicular regulatory mechanisms

Studies in vitro and in vivo indicate that steroid secretion by granulosa cells of the developing follicle is modulated in part by steroid hormones themselves. Androgens stimulate progestin synthesis in vitro by granulosa cells of all developmental stages independently of their role as an estrogen precursor; generally, the action of estradiol results in suppression of progesterone secretion. The nature of the relationship between steroid secretion by granulosa cells and the physiological processes of follicular development or atresia remains to be investigated in greater detail. The cellular mechanism(s) of steroidal modulation of steroid secretion is unknown but apparently does not involve changes in the number of granulosa cell LH receptors per se.

Prostaglandin F2alpha levels in human ovarian plasma in pregnancy and in a case of Halban's disease

It has been demonstrated that the ovary bearing the corpus luteum in the human is responsible for the major portion of prostaglandin F2alpha (PGF2alpha), total estrogen, and progestin production during the luteal phase of a normal menstrual cycle. This study was performed with the intent to gain more information about the secretion of PGF2alpha in conditions that prolong the life span of the corpus luteum, such as pregnancy and Halban's disease. Utilizing a specific radioimmunoassay for PGF2alpha, ovarian venous plasma levels were measured in 7 pregnant women and in a patient with Halban's disease. During the first and second trimester of pregnancy, PGF2alpha values in plasma from the active and inactive ovary were comparable and were significantly lower than concentrations in plasma from the active ovary during the luteal phase of the normal cycle. In a patient with persistent corpus luteum or Halban's disease, PGF2alpha concentrations of venous plasma from the ovary bearing the corpus luteum were significantly lower than those obtained from the contralateral ovary. These observations indirectly support the hypothesis that prostaglandins produced within the ovary may have a role in luteal regression.

Basic mechanisms of ovarian endocrine function

This review outlines the current understanding of ovarian endocrine development and regulation with both physiological and biochemical background to provide a framework applicable to problems concerning environmental agents and ovarian endocrine function. Two approaches are used. First, the endocrine regulation of follicle development and corpus luteum function is considered in the classical sense, i.e., viewing these structures as gonadotropin-responsive units undergoing a programmed sequence of development and differentiation. Secondly, a relatively new area of ovarian physiology concerned with intra-ovarian regulation is explored, since this area holds potential for exploration of the direct effects of toxicological or environmental agents upon gonadal endocrine cells.

Reduction of granulosa cell progesterone secretion in vitro by intraovarian implants of antiandrogen

Intra-ovarian Silastic implants containing the antiandrogen, Flutamide, or its active metabolite, reduced the level of progesterone secretion in porcine granulosa cell cultures by approximately 50%. These results complement recent observations in vitro suggesting a role for androgen in granulosa cell steroidogenesis during follicular development.

Whole and disaturated lung phosphatidylcholine in cortisol-treated, intrauterine growth-retarded and twin control lambs at different gestational ages

Lambs 116--124 days gestation infused in utero for 75 h with cortisol showed, when compared to twin controls, more mature lung histology and pressure-volume relationships. 32P orthophosphate incorporation into whole lung phosphatidylcholine (PC) was increased in the four cortisol-treated lambs at 116--117 days but not at 121, 123, and 124 days gestation. 14C palmitate incorporation into PC or disaturated phosphatidylcholine (DSPC) was not enhanced at 116--117 days gestation. At 121 days in a cortisol-treated and at 128 days in a growth-retarded lamb fetus not treated with cortisol, a larger quantity of DSPC was present although the incorporation of 14C palmitate into DSPC per milligram DNA was the same. This indicated that the synthesis of DSPC had been initiated in the cortisol-treated and growth-retarded animals prior to the controls and at the time of sacrifice both were incorporating 14C palmitate at a similar rate suggesting similar rates of synthesis.

Plasma prostaglandin F 2-alpha levels in dysmenorrehic women

Plasma prostaglandin F 2-alpha (PGF 2-alpha) concentrations were compared in nine ovulatory dysmenorrheic women, one dysmenorrheic oral contraceptive user, and two nondysmenorrheic control subjects, in an effort to demonstrate a relationship between plasma PGF 2-alpha levels and dysmenorrhea. In addition, the effects of aspirin, a known inhibitorof prostaglandins synthesis, on dysmenorrhea and on PGF 2-alpha levels were investigated. No statistical difference was demonstrated between the plasma PGF 2-alpha levels of dysmenorrheic and nondysmenorrheic subjects throughout the menstrual cycle. Attainment of an adequate salicylate level was accompanied by a significant decrease in PGF 2-alpha levels. All dysmenorrheic subjects reported improvement in symptoms while taking aspirin. The greatest subjective relief was reported by women who began taking aspirin (10 grains every 4 hours) 3 or more days prior to the onset of bleeding.

Vasomotor symptoms, serum estrogens, and gonadotropin levels in surgical menopause

Hormonal parameters of young women who developed vasomotor symptoms in the immediate postoperative period following castration are compared to those who remained asymptomatic. Only 37.5 per cent of 16 premenopausal women developed "hot flushes" after operation. Perimenopausal women with vasomotor symptoms and elevated follicle-stimulating hormone levels demonstrated normal luteinizing hormone and estrogen values preoperatively. There were no statistically significant differences in total serum estrogen, follicle-stimulating hormone, or luteinizing hormone concentrations between the group of patients with symptoms and the group withoyt symptoms. The results of the study indicate that rising gonadotropin or declining estrogen values appear to have no direct correlation to the onset of vasomotor symptoms in the immediate postoperative period. Thus, the precise etiology of the "hot flush" remains to be elucidated.

Changes in (125I) labeled human chorionic gonadotropin (hCG) binding to porcine granulosa cells during follicle development and cell culture

The specific binding of (125I)iodo human chorionic gonadotropin to porcine granulosa cells isolated at two stages of follicle maturation was quantitated immediately after harvest and following 6-7 days of culture. Both porcine LH (pLH, LER 786-3) and hCG inhibited (125I)iodo hCG binding, while pFSH (ler-1132) did not compete for hCG with granulosa cells for 24-48 hours at 37 C did not alter its subsequent ability to bind to fresh cells. The binding of (125I)iodo hCG was a rapid process which was not readily reversible. Scatchard analysis of the equilibrium binding data resulted in linear plots showing the hCG binding capacity of highly differentiated (HD) cells, harvested from large preovulatory follicles, to be significantly greater than that of moderately differentiated (MD) cells isolated from smaller luteal phase follicles, both before (794 vs 93 pmoles/g; P less than 0.001) and after (157 vs 5 pmoles/g; P less than 0.001) culture. A decline in binding capacity occurred in both cell groups during culture and was associated with a significant decrease in progestin production. In contrast, the hCG binding affinity of the granulosa cell was equivalent at both stages of follicle development and remained unchanged after 6 days of culture (mean apparent Kd = 2.9 x 10-10M; n=27. These data indicate that porcine granulosa cells contain a homogeneous class of LH receptors whose number, but not affinity, increases during follicle maturation in vivo. The loss of receptors in vitro suggests the absence of some factors(s), as yet unidentified, critical to the maintenance and development of the receptor population.

A physiologic model of the dehydroepiandrosterone to estrogen conversion system in the fetoplacental unit. II. Preliminary clinical application--the dehydroepiandrosterone loading test

A dehydroepiandrosterone (DHEA) loading test (DLT) is described. The results of 19 DHEA loading tests in as many third-trimester obstetric patients are presented. Analysis involves inspection of the raw data and the application of the physiologic model of the DHEA to estrogen conversion system described in the preceding paper (Part I). The DLT results show that within the population studied, the conversion rate of DHEA to estrogens is lower in patients with placental insufficiency than in normal patients (N = 5, p = 0.002) or in patients with various complications of pregnancy who deliver normally grown, undistressed infants (N = 6, p = 0.001). Routine clinical application must await more extensive evaluation to preclude the existence of forms of placental insufficiency not detected by this means, or normal states resulting in "false-positive" tests. These initial clinical results are intended primarily to demonstrate the potential clinical applicability of the physiologic model described in Part I.

A physiologic model of the dehydroepiandrosterone to estrogen conversion system in the fetoplacental unit. I. Development

A physiologic model of the dynamics of fetoplacental unit dehydroepiandrosterone (HDEA) to estrogen conversion is presented. A mathematical representation of this model is included. The model is used in Part II to determine the rate constant of DHEA to estrogen conversion and to successfully identify those fetuses in jeopardy from placental insufficiency within the population studied. This presentation permits critical comprehension of the model without extensive mathematical background.